sync code with last improvements from OpenBSD

xserver/hw/xfree86/os-support/linux/lnx_kmod.c

@@ -0,0 +1,111 @@
+
+#ifdef HAVE_XORG_CONFIG_H
+#include <xorg-config.h>
+#endif
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include "xf86_OSlib.h"
+#include "xf86.h"
+
+#define MODPROBE_PATH_FILE      "/proc/sys/kernel/modprobe"
+#define MAX_PATH                1024
+
+#if 0
+/* XFree86 #defines execl to be the xf86execl() function which does
+ * a fork AND exec.  We don't want that.  We want the regular,
+ * standard execl().
+ */
+#ifdef execl
+#undef execl
+#endif
+#endif
+
+/*
+ * Load a Linux kernel module.
+ * This is used by the DRI/DRM to load a DRM kernel module when
+ * the X server starts.  It could be used for other purposes in the future.
+ * Input:
+ *    modName - name of the kernel module (Ex: "tdfx")
+ * Return:
+ *    0 for failure, 1 for success
+ */
+int
+xf86LoadKernelModule(const char *modName)
+{
+    char mpPath[MAX_PATH] = "";
+    int fd = -1, status;
+    pid_t pid;
+
+    /* get the path to the modprobe program */
+    fd = open(MODPROBE_PATH_FILE, O_RDONLY);
+    if (fd >= 0) {
+        int count = read(fd, mpPath, MAX_PATH - 1);
+
+        if (count <= 0) {
+            mpPath[0] = 0;
+        }
+        else if (mpPath[count - 1] == '\n') {
+            mpPath[count - 1] = 0;      /* replaces \n with \0 */
+        }
+        close(fd);
+        /* if this worked, mpPath will be "/sbin/modprobe" or similar. */
+    }
+
+    if (mpPath[0] == 0) {
+        /* we failed to get the path from the system, use a default */
+        strcpy(mpPath, "/sbin/modprobe");
+    }
+
+    /* now fork/exec the modprobe command */
+    /*
+     * It would be good to capture stdout/stderr so that it can be directed
+     * to the log file.  modprobe errors currently are missing from the log
+     * file.
+     */
+    switch (pid = fork()) {
+    case 0:                    /* child */
+        /* change real/effective user ID to 0/0 as we need to
+         * preinstall agpgart module for some DRM modules
+         */
+        if (setreuid(0, 0)) {
+            xf86Msg(X_WARNING, "LoadKernelModule: "
+                    "Setting of real/effective user Id to 0/0 failed");
+        }
+        setenv("PATH", "/sbin", 1);
+        execl(mpPath, "modprobe", modName, NULL);
+        xf86Msg(X_WARNING, "LoadKernelModule %s\n", strerror(errno));
+        exit(EXIT_FAILURE);     /* if we get here the child's exec failed */
+        break;
+    case -1:                   /* fork failed */
+        return 0;
+    default:                   /* fork worked */
+    {
+        /* XXX we loop over waitpid() because it sometimes fails on
+         * the first attempt.  Don't know why!
+         */
+        int count = 0, p;
+
+        do {
+            p = waitpid(pid, &status, 0);
+        } while (p == -1 && count++ < 4);
+
+        if (p == -1) {
+            return 0;
+        }
+
+        if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {
+            return 1;           /* success! */
+        }
+        else {
+            return 0;
+        }
+    }
+    }
+
+    /* never get here */
+    return 0;
+}